Alterations in cerebrospinal fluid uridine,hypoxanthine, and xanthine in head-injured patients

1. Examination of the cerebrospinal fluid (CSF) of head-injured patients reveals that the concentration of intraventricular xanthine is elevated and that of uridine is decreased relative to those of adult lumbar CSF. 2. No correlations were observed between CSF lactate and CSF hypoxanthine, xanthine, or uridine, suggesting that changes in purine metabolites and the pyrimidine nucleoside do not index similar cellular events as does lactic acid production. 3. Ventricular CSF from hydrocephalic infants had uridine and hypoxanthine concentrations not significantly different from those of normal adult lumbar CSF, but xanthine was significantly elevated. 4. Since uridine has anticonvulsant properties and is a crucial substrate for cerebral metabolism, it may be useful to evaluate this pyrimidine for use in the management of patients with head injury.     

Purification and properties of human placental acid lipase

Two peaks of lysosomal acid lipase activity were purified from normal human placenta. Acid lipase I, with an estimated molecular weight of 102 500, was purified 1016-fold while acid lipase II, with an estimated molecular weight of 30 600, was purified 3031-fold. The final yields of enzyme activity for acid lipase I and II were 0.9% and 2.2% respectively. The purity of the final preparations was documented by demonstration of a single protein band on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Both preparations of the purified enzyme demonstrated activity towards triolein, cholesteryl oleate and the artificial substrate 4-methylumbelliferyl oleate. Examination of Km values, thermal stability, pH optima, and electrophoretic mobility revealed similar properties for the two enzyme peaks. The response of the two enzyme preparations to inhibitors was similar with both being significantly inhibited by 0.2 M NaCl, 0.2 M KCl, 5 mM HgCl2 and 5 mM p-chloromercuribenzoate. The activity of the two preparations as assayed with either triolein or cholesterol oleate was not significantly affected by the addition of bovine serum albumin. In contrast, the 4-methylumbelliferyl oleate activity of both preparations was significantly inhibitred by albumin. These findings support the hypothesis that the same enzyme or enzymes are responsible for the intralysosomal hydrolysis of triacylglycerols and cholesterol esters in human tissues.     

Bone Morphogenetic Protein 7 (BMP-7) Influences Tendon-Bone Integration In Vitro

IntroductionSuccessful graft ingrowth following reconstruction of the anterior cruciate ligament is governed by complex biological processes at the tendon-bone interface. The aim of this study was to investigate in an in vitro study the effects of bone morphogenetic protein 7 (BMP-7) on tendon-bone integration.ResultsIn both models, positive effects of BMP-7 on ALP enzyme activity were observed (p<0.001). Additionally, similar results were noted for LDH activity and lactate concentration. BMP-7 stimulation led to a significant increase in OCN expression. Whereas the effects of BMP-7 on tendon monoculture peaked during an early phase of the experiment (p<0.001), the cocultures showed a maximal increase during the later stages (p<0.001). The histological analysis showed a stimulating effect of BMP-7 on extracellular matrix formation. Organized ossification zones and calcium carbonate-like structures were only observed in the BMP-stimulated cell cultures.DiscussionThis study showed the positive effects of BMP-7 on the biological process of tendon-bone integration in vitro. Histological signs of improved mineralization were paralleled by increased rates of osteoblast-specific protein levels in primary bovine osteoblasts and fibroblasts.ConclusionOur findings indicated a role for BMP-7 as an adjuvant therapeutic agent in the treatment of ligamentous injuries, and they emphasized the importance of the transdifferentiation process of tendinous fibroblasts at the tendon-bone interface.     

Cell adhesion molecule in the hexactinellid Aphrocallistes vastus

Abstract. The Hexactinellida sponge Aphrocallistes vastus contains a soluble aggregation factor (AF) whose purification has been described in this communication. It is characterized by a S°_20.w value of 37 and a buoyant density of 1.45 g/cm³. The AF is a glycoporteinaceous particle composed of three major protein species; no core structure could be visualized. In the presence of Ca²⁺, the AF causes secondary aggregation of single cells. The aggregation process is temperature, pH, and ionic strength independent within a broad range. Evidence is presented indicating that two (or more) AF molecules are required for the establishment of a stable cell: cell interaction. In contrast to the AFs from demosponges, the hexactinellid AF functions species-unspecifically.     

Molecular cloning and expression of human trophoblast antigen FDO161G and its identification as 3 beta-hydroxy-5-ene steroid dehydrogenase

The monoclonal antibody FDO161G reacts with a 43-kDa protein found in human extravillous trophoblast, syncytiotrophoblast, adrenal cortex, interstitial cells of the testis and ovarian follicle cumulus cells. cDNAs for this protein have been isolated from the lambda gt11 library, sequenced, and expressed in COS-7 cells. The protein was identified as 3 beta-hydroxy-5-ene steroid dehydrogenase (HSD). The sequence of the HSD protein raises questions about its association with cell membrane systems. The lack of reactivity of FDO161G with other tissues suggests that HSD has a limited tissue distribution and that other enzymes may exist in peripheral tissues, which can convert delta 5 3-hydroxysteroids to delta 4 3-ketosteroids.     

Two novel loci underlie natural differences in Caenorhabditis elegans abamectin responses

Parasitic nematodes cause a massive worldwide burden on human health along with a loss of livestock and agriculture productivity. Anthelmintics have been widely successful in treating parasitic nematodes. However, resistance is increasing, and little is known about the molecular and genetic causes of resistance for most of these drugs. The free-living roundworm Caenorhabditis elegans provides a tractable model to identify genes that underlie resistance. Unlike parasitic nematodes, C. elegans is easy to maintain in the laboratory, has a complete and well annotated genome, and has many genetic tools. Using a combination of wild isolates and a panel of recombinant inbred lines constructed from crosses of two genetically and phenotypically divergent strains, we identified three genomic regions on chromosome V that underlie natural differences in response to the macrocyclic lactone (ML) abamectin. One locus was identified previously and encodes an alpha subunit of a glutamate-gated chloride channel (glc-1). Here, we validate and narrow two novel loci using near-isogenic lines. Additionally, we generate a list of prioritized candidate genes identified in C. elegans and in the parasite Haemonchus contortus by comparison of ML resistance loci. These genes could represent previously unidentified resistance genes shared across nematode species and should be evaluated in the future. Our work highlights the advantages of using C. elegans as a model to better understand ML resistance in parasitic nematodes.     

Correlation of adenosine receptor affinities and cardiovascular activity

Binding affinities of 28 adenosine analogs at A1 adenosine receptors (rat whole brain membranes, [3H]N6-cyclohexyladenosine, CHA), and at A2 adenosine receptors (rat striatal membranes, [3H]NECA) were compared to their EC25 values for decreasing heart rate and increasing coronary flow in the isolated rat heart. Heart rate (an A1 response) correlated with A1 binding affinity (r2 = 0.71, p less than 0.0001) but not with A2 binding affinity (r2 = 0.007, n.s.); conversely, coronary flow (an A2 response) correlated with A2 binding affinity (r2 = 0.83, p less than 0.0001) but not with A1 binding affinity (r2 = 0.05, n.s.). These results confirm that the brain A1 and A2 receptors, studied by binding methods, bear close similarities to their respective counterparts in the heart, studied by means of functional responses.     

Dsi-1, a region with frequent proviral insertions in Moloney murine leukemia virus-induced rat thymomas.

Dsi-1 is a region of chromosomal DNA that underwent proviral insertion in 3 of 24 Moloney murine leukemia virus-induced rat thymomas. In one of these tumors, a provirus is also integrated adjacent to the proto-oncogene c-myc. The proviruses in Dsi-1 have been characterized and appear to be complete. The proviruses were located within a 2-kilobase region that contained four prominent DNase I-hypersensitive sites. These hypersensitive sites were observed in Moloney murine leukemia virus-induced thymomas but not in NRK cells. The region of Dsi-1 immediately 3' to the insertions cross-hybridized with human and chicken DNA, indicating that it contains highly conserved sequences. No evidence could be found for the expression of this highly conserved region. Dsi-1 was mapped to mouse chromosome 4. This location demonstrates that Dsi-1 is different from 16 of the known proto-oncogenes (c-abl, c-erbA c-erbB, c-ets-1, c-ets-2, c-fes, c-fos, c-myb, c-myc, c-raf, A-raf, c-Ha-ras, c-Ki-ras, N-ras, c-sis, and c-src) and 12 cellular regions of tumor-associated integrations in retrovirus-induced tumors (c-erbB, Fis-1, int-1, int-2, Mis-1/pvt-1, Mlvi-1, Mlvi-2, c-mos, c-myb, c-myc, Pim-1, and c-Ha-ras). Hybridization experiments indicated that Dsi-1 is probably different from five additional proto-oncogenes (c-fgr, c-fms, c-mos, neu, and c-yes) and from two additional frequent integration regions (lck and Mlvi-3).